Notch3-specific inhibition using siRNA knockdown or GSI sensitizes paclitaxel-resistant ovarian cancer cells.

Notch signaling plays an important role in ovarian cancer chemoresistance, which is responsible for recurrence. Gamma-secretase inhibitor (GSI) is a broad-spectrum Notch inhibitor, but it has serious side effects. The efficacy of Notch3-specific inhibition in paclitaxel-resistant ovarian cancers was assessed in this study, which has not yet been evaluated relative to GSI. To analyze the effect of Notch3-specific inhibition on paclitaxel-resistant ovarian cancers, we compared cell viability, apoptosis, cell migration, angiogenesis, cell cycle, and spheroid formation after treatment with either Notch3 siRNA or GSI in paclitaxel-resistant SKpac cells and parental SKOV3 cells. Expression levels of survival, cell cycle, and apoptosis-related proteins were measured and compared between groups. Notch3 was significantly overexpressed in chemoresistant cancer tissues and cell lines relative to chemosensitive group. In paclitaxel-resistant cancer cells, Notch inhibition significantly reduced viability, migration, and angiogenesis and increased apoptosis, thereby boosting sensitivity to paclitaxel. Spheroid formation was also significantly reduced. Both Notch3 siRNA-treated cells and GSI-treated cells arrested in the G2/M phase of the cell cycle. Proteins of cell survival, cyclin D1 and cyclin D3 were reduced, whereas p21 and p27 were elevated. Both GSI and Notch3 siRNA treatment reduced expression of anti-apoptotic proteins (BCL-W, BCL2, and BCL-XL) and increased expression of pro-apoptotic proteins (Bad, Bak, Bim, Bid, and Bax). These results indicate that Notch3-specific inhibition sensitizes paclitaxel-resistant cancer cells to paclitaxel treatment, with an efficacy comparable to that of GSI. This approach would be likely to avoid the side effects of broad-spectrum GSI treatment. © 2015 Wiley Periodicals, Inc.

Microneedle fractional radiofrequency increases epidermal hyaluronan and reverses age-related epidermal dysfunction.

BACKGROUND AND OBJECTIVE: Skin aging results in physiological alterations in keratinocyte activities and epidermal function, as well as dermal changes. Yet, the cellular and molecular mechanisms that cause epidermal dysfunction during skin aging are not well understood. Recently, the role of epidermal hyaluronan (HA) as an active regulator of dynamic cellular processes is getting attention and alterations in HA metabolism are thought to be important in age-related epidermal dysfunction. Microneedle fractional radiofrequency (RF) has shown effects for improving cutaneous aging. However, little is known about the effects of fractional RF on the epidermal HA and epidermal function. We investigated the effect of microneedle fractional RF on the expression of epidermal HA in young and aged mice epidermis. MATERIALS AND METHODS: We performed fractional RF on the dorsal skin of 30 8-week-old (young) hairless mice and 15 47-week-old (aged) C57BL/6J mice. Skin samples were collected on day 1, 3, and 7. HA content was measured by ELISA. Gene expressions of CD 44, HABP4, and HAS3 were measured using real time RT-PCR. Immunohistochemistry for detection of HA, CD44, PCNA, and filaggrin were performed. RESULTS: HA content and the mRNA levels of HABP4, CD44, and HAS3 were upregulated in the epidermis of both young and aged mice after microneedle fractional RF treatment. The expression was increased from day 1 after treatment and increased expression persisted on day 7. Fractional RF treatment significantly increased PCNA and filaggrin expression only in the aged mice skin. CONCLUSION: Microneedle fractional RF increased epidermal HA and CD44 expression in both young and aged mice and reversed age-related epidermal dysfunction especially in aged mice, suggesting a new mechanism involved in the skin rejuvenation effect of microneedle fractional RF.

Notch3 and Jagged2 contribute to gastric cancer development and to glandular differentiation associated with MUC2 and MUC5AC expression.

AIMS: Notch signalling plays diverse roles in malignant tumours as well as in normal tissue development. In this study we investigated the expression of Notch signalling pathway genes and their clinicopathological significance in gastric carcinomas. METHODS AND RESULTS: Notch1, Notch3, Jagged1, Jagged2 and Hes1 expression were analysed by quantitative real-time polymerase chain reaction (qRT-PCR) (n = 81) and immunohistochemistry (n = 103) in gastric carcinomas. MUC2 and MUC5AC expression were also assessed, using immunohistochemistry only. With qRT-PCR, Notch1, Notch3, Jagged1 and Jagged2 expression were increased significantly in tumour compared to normal tissue (P < 0.001, P = 0.002, P = 0.008 and P < 0.001, respectively). Overexpression of Notch3 and Jagged2 was associated with intestinal-type carcinomas (P = 0.024) and better histological differentiation (P = 0.047), respectively. Immunohistochemistry showed a reverse correlation between MUC2 and Notch3 or Jagged1 (P = 0.033 and P = 0.005, respectively) and between MUC5AC and Jagged1 or Hes1 (P = 0.004 and P = 0.002, respectively). Notch3 and Jagged2 gene overexpression related to a favourable outcome on univariate (P = 0.046 and P = 0.042, respectively) and multivariate (P = 0.045, Notch3) analysis. CONCLUSION: The expression of Notch3 and Jagged2 is associated not only with gastric cancer development but also with the intestinal/glandular differentiation of gastric carcinoma cells, suggesting a role as a possible favourable prognostic indicator.

Acute liver toxicity by carbon tetrachloride in HSP70 knock out mice.

The effects of carbon tetrachloride (CCl(4)) treatment on acute liver damage in knock out (heat shock proteins -- HSP70-/-) mice and wild-type (C57BL/6) mice were examined. Acute liver injury was induced by a single intraperitoneal injection of 0.3 ML/kg CCl(4) in olive oil. Mice were sacrificed at 12, 24, 48 and 72 h after treatment. To assess hepatotoxicity, alanine transaminase, neutrophil infiltration and degree of necrosis were measured. Western blot analysis was employed for heat shock proteins. The result revealed that HSP70-/- mice showed higher alanine transaminase levels and a more severe degree of neutrophilic infiltration and necrosis than those of wild-type mice. Furthermore, HSP70-/- mice recovered more slowly from CCl(4) treatment. In HSP70-/- mice, HSP47 was overexpressed. Therefore, HSP70-/- mice could be an adequate model of acute liver toxicity study.

Hsa-miR-1246 and hsa-miR-1290 are associated with stemness and invasiveness of non-small cell lung cancer.

OBJECTIVES: Cancer stem cells (CSCs) are considered to play a pivotal role in the process of invasion, metastasis and chemotherapy resistance. Diverse aberrantly expressed microRNAs (miRNAs) have been reported in lung cancer cells. However, there have been few reports about miRNAs that were associated with stemness and invasion of lung cancer. We investigated the role of miRNAs associated with characteristics of CSCs in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: We cultured A549 cells (lung adenocarcinoma) and HCC1588 cells (lung squamous cell carcinoma) in serum free media condition. We isolated sphere-forming NSCLC cells and examined the microRNA expression by microarray and qRT-PCT. By inhibition of CSC-associated microRNAs, we identified the changes of stemness and invasiveness in NSCLC. RESULTS AND CONCLUSION: We discovered 44 over-expressed, 42 down-regulated miRNAs in the sphere-forming cells compared with the parent cells of NSCLC. By in-silico database search, we selected miR-1246 and miR-1290 that were suspected to be associated with CSCs among aberrantly expressed miRNAs. Inhibition of miR-1246 and miR-1290 showed decreased stemness markers and epithelial-mesenchymal transition (EMT) markers in NSCLC. Anti-miR-1246 and anti-miR-1290 suppressed proliferation, sphere-formation, colony formation and invasion of NSCLC. CSCs-associated miR-1246, or miR-1290 may be important in the invasion or metastasis of NSCLC.

Fibulin-5 is a tumour suppressor inhibiting cell migration and invasion in ovarian cancer.

AIMS: Fibulin-5 is an extracellular matrix (ECM) glycoprotein which has a role in the organisation and stabilisation of ECM structures and regulating cell proliferation and tumourigenesis. Here, the expression of fibulin-5 and its functional effects on the migration and invasion of ovarian cancer cells were assessed. METHODS: Expression of fibulin-5 was detected in 44 ovarian tumour tissues by qRT-PCR, Western blotting and immunohistochemistry. We performed cell migration and invasion assays, and cell cycle analysis in fibulin-5 transfected SKOV3 (SKOV3-FBLN5) cells and the parental SKOV3 cells. We further examined the expression of three tissue inhibitors of metalloproteinases (TIMPs) and seven matrix metalloproteinases (MMPs) by RT-PCR. RESULTS: mRNA and protein expression of fibulin-5 were down-regulated (0.05-fold and 0.1-fold) in ovarian carcinomas compared with control tissues (p<0.01 and p=0.022). In wound-healing and invasion assays, significantly fewer SKOV3-FBLN5 cells than SKOV3 control cells migrated and invaded (39.1%, p=0.046 and 70%, p=0.03, respectively), which was reversed by siRNA-treatment. Overexpression of fibulin-5 induced G2/M arrest and increased cyclin B1, CDC2 and CDC25C. Expression of TIMP-2 (0.56-fold), MMP-3 (0.43-fold) and MMP-13 (0.18-fold) was lower and MMP-9 expression (2.20-fold) was higher in SKOV3-FBLN5 cells than in control cells. CONCLUSIONS: Fibulin-5 is significantly down-regulated in ovarian carcinoma and acts as a tumour suppressor by inhibiting the migration and invasion of ovarian cancer cells.

[Research on the mechanisms of PTEN gene inactivation in ovarian cancer].

OBJECTIVE: To investigate the mechanisms of PTEN gene inactivation starting from DNA, mRNA and protein levels in ovarian cancers. METHODS: Tumor tissue samples were obtained from 48 patients with epithelial ovarian cancers. Using four polymorphic markers (D10s541, D10s583, D10s1687 and D10s2491) within and flanking the PTEN gene located in chromosome 10q 23.3, polymerase chain reaction (PCR) and loss of heterozygosity (LOH) were introduced to examine LOH of PTEN gene; PCR-single strand conformation polymorphism (PCR-SSCP) was introduced to examine mutations of the fifth, sixth, seventh, and eighth exons of PTEN. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (SP method) were applied to detect PTEN mRNA and PTEN protein expressions, respectively. RESULTS: LOH of PTEN gene was observed in 19 of 48 (39.6%) ovarian cancers. PTEN mutations were found only in 2 (4.2%) of the cases. Absence of PTEN mRNA expression was 18.8% (9 of 48). Immunostaining of 48 cancer samples revealed that 13 (27.1%) were PTEN immunostain negative. Of these 13 samples, only 2 (15.4%) had structural, biallelic inactivation by intragenic PTEN mutations and loss of the remaining wild-type allele; 7 (53.8%) showed evidence of LOH, 5 of these 7 samples showed deletion of PTEN mRNA expression, another 2 samples showed positive expression of PTEN mRNA; 4 (30.8%) tumors had neither PTEN gene mutation nor LOH but exhibited no PTEN protein expression, 2 of these 4 cases showed deletion of PTEN mRNA expression, another 2 showed positive expression of PTEN mRNA. For the cases of PTEN protein absent staining, the rate of LOH was 69.2% (9 of 13), higher than 28.6% (10 of 35) for the positive staining (P < 0.05). CONCLUSIONS: PTEN gene inactivation may contribute to epithelial ovarian carcinogenesis. There may be several mechanisms of PTEN gene inactivation in ovarian cancers. Protein expression deletions may be a significant mechanism.

miR-145, targeting high-mobility group A2, is a powerful predictor of patient outcome in ovarian carcinoma.

MicroRNA-145 (miR-145) expression is downregulated in several human cancers, but its clinical and functional relevance to ovarian carcinoma has not yet been elucidated. This study addressed the hypothesis that miR-145 serves as a prognostic biomarker and a tumor suppressor that regulates the expression of high-mobility group A2 (HMGA2) oncoprotein in ovarian cancer. Here, we found that low miR-145 expression and HMGA2 overexpression determined by qRT-PCR and immunohistochemistry significantly correlated with advanced stage, lymph node involvement, and distant metastasis in 74 ovarian carcinomas. Low miR-145 expression significantly correlated with tumor recurrence and worse overall survival (HR=8.62, P = 0.039). Transfection of pre-miR-145 resulted in reduced cell growth and migration, and increased apoptosis of ovarian cancer cells by TUNEL, colony forming, and cell migration assays. MiR-145 was found to directly target HMGA2 by luciferase assay and Western blotting. Our findings suggest that miR-145 functions as a tumor suppressor in ovarian cancer and directly targets HMGA2 oncoprotein. Low miR-145 and high HMGA2 expressions are potential biomarkers of poor prognosis of ovarian carcinoma and miR-145 is the more powerful predictor of patient outcome.

VAV3 Overexpressed in Cancer Stem Cells Is a Poor Prognostic Indicator in Ovarian Cancer Patients.

Ovarian carcinoma is a highly lethal malignancy due to frequent relapse and drug resistance. Cancer stem cells (CSCs) are thought to contribute significantly to disease relapse and drug resistance. In this study, a subpopulation of CSCs of ovarian carcinoma was isolated and the genes differentially expressed in these cells were identified to characterize CSCs and to find candidate biomarkers. Ovarian carcinoma cells from patients were primarily cultured, and spheroid-forming cells (SFCs) were isolated. The characteristic genes of SFCs were identified through cDNA microarray and validation by quantitative real-time polymerase chain reaction and immunohistochemistry, and the association of their expression with clinicopathologic parameters was analyzed. GSC (4.26-fold), VAV3 (7.05-fold), FOXA2 (12.06-fold), LEF1 (17.26-fold), COMP (21.33-fold), GRIN2A (9.36-fold), CD86 (23.14-fold), PYY (4.18-fold), NKX3-2 (10.35-fold), and PDK4 (74.26-fold) were significantly upregulated in SFCs compared with parental cancer cells. With validation for human ovarian carcinomas, LEF1, PYY, NKX3-2, and WNT3A were significantly upregulated in chemoresistant cancers compared with chemosensitive cancers. Overexpression of LEF1, VAV3, and NKX3-2 was significantly associated with distant metastasis by immunohistochemistry. VAV3 overexpression was an independent poor survival indicator (hazard ratio=15.27, P<0.05) by multivariate Cox analysis. The further functional assay revealed that VAV3 knockdown regulated CSC activation and ovarian cancer cell proliferation and sensitized paclitaxel (PTX)-resistant cancer cells to PTX treatment. Taken together, we identified by high-throughput analysis of CSCs that VAV3 overexpression is a novel biomarker for poor prognosis and survival in ovarian carcinoma.

Fascin1 expression in high-grade serous ovarian carcinoma is a prognostic marker and knockdown of fascin1 suppresses the proliferation of ovarian cancer cells.

Fascin1 (FSCN1) involved in cell motility and filopodia assembly plays important roles in biological processes such as cancer invasion and metastasis of multiple epithelial tumors. High-grade serous ovarian carcinoma (HGSOC) is aggressive and metastatic by acquiring an invasive phenotype and this step requires remodeling of the actin cytoskeleton. Thus, the present study aimed to investigate the expression of fascin1 in HGSOC tissues as well as its clinical significance such as prognostic predictors and its utility of therapeutic target. Fascin1 and ß-catenin were evaluated using immunohistochemistry on a tissue microarray of 79 HGSOC. Small interfering RNA (siRNA) approach was used to knock down fascin1 expression in ovarian cancer cell lines to determine whether fascin1 contributes to tumor cell proliferation, migration and invasion. Fascin1 expression levels were determined by western blot analysis after siRNA transfection using two human ovarian cancer cell lines (SKOV3 and OVCAR3). Fascin1 overexpression was significantly correlated with lymph node involvement, distance metastasis and high International Federation of Gynecology and Obstetrics (FIGO) stage (III/IV) (P<0.05). A Kaplan-Meier analysis showed that the fascin1 expression group was significantly associated with poor overall survival (P=0.010). We showed that inactivation of fascin1 by siRNA transfection led to a drop in cell viability, and significantly decreased tumor cell proliferation, migration and invasiveness compared to untransfected cells. We found that fascin1 expression is a potential poor marker of prognosis for patients with HGSOC and knockdown of fascin1 suppresses ovarian cancer cell proliferation and migration, this could be applied for therapeutic targets in ovarian cancer treatment.

Plasma heart-type fatty acid binding protein level in acute ischemic stroke: comparative analysis with plasma S100B level for diagnosis of stroke and prediction of long-term clinical outcome.

OBJECTIVES: Heart-type fatty acid binding protein (H-FABP) is enriched in neuronal cell body as well as myocardium, and is rapidly released from damaged neuron into circulation in cerebral ischemia. We performed a comparative analysis between plasma H-FABP and S100B levels in the acute phase of ischemic stroke. METHODS: The present study included 111 consecutive patients with acute ischemic stroke and 127 control subjects. Measurement of plasma H-FABP and S100B levels was conducted during acute phase (<24 h) of stroke. Clinical severities were evaluated by the use of NIHSS scores at admission and mRS score at 3 months after symptom onset. RESULTS: Both the plasma H-FABP and S100B levels were significantly higher in stroke group than control group. In multiple logistic regression analysis, statistical significance of both markers remained significant after adjusting the vascular risk factors. In the receiver operator characteristic (ROC) curve analysis, neither H-FABP (area under curve [AUC]=0.71, P<0.001, sensitivity: 59.5%, specificity: 79.5%) nor S100B (AUC=0.70, P<0.001, sensitivity: 54.0%, specificity: 83.5%) showed a favorable degree of diagnostic value to discriminate stroke from stroke mimic. Plasma H-FABP (r=0.46, P<0.01) and S100B (r=0.45, P<0.01) were correlated with initial NIHSS score, and both marker were significantly higher in patients with poor clinical outcome. CONCLUSION: Although plasma H-FABP is elevated in the acute phase of ischemic stroke, the diagnostic accuracy of H-FABP as a sole marker is not sufficient to be applied in the clinical setting. Plasma H-FABP can be used as a potential marker for stroke prognosis.

Effects of corticosteroid on the expressions of neuropeptide and cytokine mRNA and on tenocyte viability in lateral epicondylitis.

BACKGROUND: The purpose of this study was to determine the reaction mechanism of corticosteroid by analyzing the expression patterns of neuropeptides (substance P (SP), calcitonin gene related peptide (CGRP)) and of cytokines (interleukin (IL)-1α, tumor growth factor (TGF)-ß) after corticosteroid treatment in lateral epicondylitis. In addition, we also investigated whether corticosteroid influenced tenocyte viability. METHODS: The corticosteroid triamcinolone acetonide (TAA) was applied to cultured tenocytes of lateral epicondylitis, and the changes in the mRNA expressions of neuropeptides and cytokines and tenocyte viabilities were analyzed at seven time points. Quantitative real-time polymerase chain reaction and an MTT assay were used. RESULTS: The expression of SP mRNA was maximally inhibited by TAA at 24 hours but recovered at 72 hours, and the expressions of CGRP mRNA and IL-1α mRNA were inhibited at 24 and 3 hours, respectively. The expression of TGF-ß mRNA was not significant. Tenocyte viability was significantly reduced by TAA at 24 hours. CONCLUSIONS: We postulate that the reaction mechanism predominantly responsible for symptomatic relief after a corticosteroid injection involves the inhibitions of neuropeptides and cytokines, such as, CGRP and IL-1α. However the tenocyte viability was compromised by a corticosteroid.

Interleukin-1ß induces angiogenesis and innervation in human intervertebral disc degeneration.

Degenerative disorders of the intervertebral discs (IVDs) are generally characterized by enhanced matrix degradation, angiogenesis, innervation, and increased expression of catabolic cytokines. In this study, we investigated the effects of inflammatory cytokines, IL-1ß, and TNF-α, on the expression of an angiogenic factor, vascular endothelial growth factor (VEGF), and neurotrophic factors, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), in human IVD degeneration. IL-1ß and TNF-α stimulated the gene expression of VEGF, NGF, and BDNF in nucleus pulposus (NP) cells isolated from patient tissues. Immunohistochemical results demonstrated a positive correlation between IL-1ß and VEGF/NGF/BDNF expression in human IVD tissues. RNA expression analysis of patient tissues also identified positive correlations between VEGF and platelet endothelial cell adhesion molecule-1 (PECAM-1) and between NGF/BDNF and protein gene product 9.5 (PGP9.5). Our findings suggest that IL-1ß is generated during IVD degeneration, which stimulates the expression of VEGF, NGF, and BDNF, resulting in angiogenesis and innervation.

[Effects of HCMV on phenotypes of parotid duct epithelial cells and its mechanisms].

OBJECTIVE: To investigate the effects of HCMV infection on phenotypes of parotid duct epithelial cells and relative mechanisms. METHODS: The expressions of immediate early antigen of HCMV, pan cytokeratin and cathepsin D etc. were detected by immunohistochemical staining in tissues of parotid cytomegalic inclusion disease. RESULTS: Cytokeratin which acts as an epithelial marker became negative while staining of Cathepsin D was intensified in parotid duct epithelial cells after infected by HCMV. CONCLUSION: It demonstrated that cytokeratin was lost through over-expression of Cathepsin D in parotid duct epithelial cells infected by HCMV.

[Relationship between expressions of telomerase genes and apoptosis related genes in mammary ductal atypical hyperplasia].

BACKGROUND & OBJECTIVE: Recent studies showed that the activating of telomerase and excessive expression of apoptosis suppressor genes were related to the development of many tumors. This study was designed to investigate the expression of telomerase genes (hTR, hTRT) and apoptosis related genes (p53, bcl-2) in mammary atypical ductal hyperplasia for exploring the change of telomerase activity and apoptosis related genes in the process of mammary ductal dysplasia to malignant transformation. METHOD: Expressions of telomerase genes (hTR, hTRT) and apoptosis related genes (p53, bcl-2) were detected by in situ hybridization and expression of the mutant p53 protein was detected by immunohistochemistry were detected in 44 patients with mammary atypical ductal hyperplasia, those expression were compared with those of the 6 benign hyperplasia and 26 breast carcinoma. RESULT: High expressions of telomerase genes (hTR, hTRT mRNA) in severe atypical ductal hyperplasia (60.9%, 52.1%) is of significantly difference from that in mild-medium atypical ductal hyperplasia (22.2%, 11.1%; 33.3%, 25.0%) and breast cancer (88.5%, 80.8%). The upgrading of atypia link with decreased expression of wild p53 mRNA (mild: 55.6%; medium: 41.7%; severe: 26.1%) and increased expression of the mutant p53 protein (mild: 11.1%; medium: 25.0%; severe: 34.8%). As for bcl-2 mRNA, it shows moderate expression, especially in severe atypical ductal hyperplasia. CONCLUSION: Our study revealed significant correlation between expressions of telomerase genes (hTR, hTRT) and the state of malignant transformation in mammary atypical ductal hyperplasia. Decreased expression of wild p53 gene, increased expression of mutant p53 protein, and overexpression of bcl-2 gene were associated with telomerase.

[Activation of phosphatidylinositol 3-kinase in human breast carcinoma].

BACKGROUND & OBJECTIVE: Phosphatidylinositol 3-kinase (PI3-K) has been implicated in the signaling pathways regulating cell growth by virtue of its activation in response to various mitogenic stimuli, but the role of PI3-K in human tumorigenesis has not yet to be defined. This study was designed to investigate the levels of both PI3-K protein and PI3-K mRNA and the activity of PI3-K in human breast tumors. METHODS: Western blot, immunoprecipitation, kinase activity assay, and RT-PCR were used to detect the expression and activity of PI3-K in 37 patients with breast cancers. RESULTS: Significantly increased expression of p85 subunit of PI3-K at levels of both protein and mRNA were found in 32 (86.49%) and 35(94.59%) out of the 37 breast tumors compared with adjacent normal tissue. Significantly higher level of the activity of PI3-kinase was observed in 25(67.57%) out of the 37 cases. CONCLUSIONS: PI3-K was highly activated in breast tumor tissue compared with adjacent normal tissue, suggesting that PI3-K was involved in the signal transduction of breast tumorigenesis. It may be a potential target for new strategies for the treatment of the patients with breast cancers.

[Human cytomegalovirus inhibits proliferation of duct epithelial cells of human salivary gland].

OBJECTIVE: To investigate the effects of human cytomegalovirus (HCMV) on the proliferation of duct epithelial cells of human salivary gland (HSG). METHODS: The expression of proliferating cell nuclear antigen (PCNA) and p53 were studied in 11 cases of parotid cytomegalic inclusive disease (PCID) using immunohistochemical staining method. The effects of human cytomegalovirus (HCMV) on the proliferation of HSG were investigated by MTT method in vitro. The expression of PCNA in HSG infected by HCMV was examined using immunocytochemical staining and Western blotting. RESULTS: PCNA was expressed weakly in most of megalic inclusion cells which were positive for HCMV, while all the megalic inclusion cells were p53 negative in all 11 cases of PCID. HCMV inhibited proliferation of HSG in vitro in a time dependent and dose dependent manner. Down-regulation of PCNA was shown in infected cells. CONCLUSION: HCMV inhibits proliferation of HSG and down-regulation of PCNA may be an expression of the inhibition.